The present invention relates to an image recognition apparatus and an image recognition method in which an image of an object to be recognized is acquired and the image is subjected to a recognizing process.
In a field of producing electronic parts or devices, an image recognition method in which the images of objects to be recognized such as electronic parts or boards are picked up by a camera and the images as the image picked-up results are recognized to identify the objects to be recognized and detect positions has been widely employed. As an example to which the image recognition method is applied, a print inspection is performed for the boards after a solder printing carried out before the electronic parts are mounted. In the print inspection, the printed state of cream solder printed on an electrode of the board, that is, a printed position or an amount of printed solder or the like is detected by recognizing the image to decide whether or not the printed state is good. For example, it is proposed in JP-A-4-104044 or JP-A-2000-2667.
A certain electrode of the board may have a solder leveler with a solder film formed on the surface of the electrode in order to improve a solder joint property. When the cream solder printed on the electrode having such as older leveler is an object to be recognized, the cream solder has been hardly identified in accordance with an image recognition. Further, the electrode on the board and the cream solder on the electrode are hardly identified at the same time. That is, to identify the cream solder, the printed part of the cream solder needs to be separated from the surface of the solder leveler in accordance with a luminance difference. However, since the solder leveler and the cream solder include the naturally same material, an apparent luminance difference hardly appears on the picked up image. Thus, a highly accurate recognition has been difficult. Further, a plurality of images picked up under different illuminating conditions need to be obtained, so that much time has been required to obtain the images and a recognition tact time has been hardly shortened.